Perinatal intervention and neonatal outcomes near the limit of viability

The purpose of this study was to evaluate trends in the level of obstetric and neonatal intervention near the limit of viability and perinatal morbidity and mortality rates over time.

In this retrospective chart review, live-born infants who were delivered at 23 to 26 weeks of gestation and who weighed between 500 and 1500 g between 1990 and 2001 in an urban tertiary care center were identified. Maternal charts were reviewed for clinical characteristics and antenatal and intrapartum course. Neonatal charts were reviewed for short-term morbidities that included respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, retinopathy of prematurity, and survival. The study group was divided into 2 cohorts (group I:1990-95; group II:1996-2001); the obstetrician's willingness to intervene, neonatal resuscitation efforts, infant mortality (in gestational age subgroups) rate, and short-term morbidity rate were compared. Multivariate analyses, which controlled for obstetrician willingness to intervene, neonatal resuscitation, cohort, and gestational age, were performed to evaluate infant survival in the entire cohort and for morbidity in the survivors.

Records for 260 mothers and 293 newborn infants were evaluated. Comparing the 2 cohorts (group I vs II), we found increases over time in intent to intervene for fetal indication (70% vs 89%; P = .0007), cesarean delivery for malpresentation (20% vs 42%; P = .0003), and survival (54% vs 70%; P = .003). Pregnancies in group 1 were less likely to have received antenatal steroids (7.7% vs 60%) or surfactant (39% vs 73%; P <.0001 for each). Survival increased with advancing delivery gestation (24%, 51%, 68%, and 85% at 23, 24, 25, and 26 weeks of gestation, respectively; P <.0001). However, among survivors, the incidences of necrotizing enterocolitis, retinopathy of prematurity, intraventricular hemorrhage, respiratory distress syndrome, sepsis, and bronchopulmonary dysplasia did not decline significantly with advancing gestational age, after controlling for other factors.

Obstetric intervention and aggressive neonatal resuscitation have increased for pregnancies delivered between 23 and 26 weeks of gestation over the past decade. Although survival has increased over time and with advancing gestational age at delivery, short-term morbidity in survivors is similar, regardless of gestational age in this cohort. A brief delay in delivery of those pregnancies who are at risk for delivery between 23 and 26 weeks of gestation may improve survival, although short-term morbidity in survivors will not be affected substantially.